RATIONALE: Drugs used in chemotherapy, such as cisplatin and fluorouracil, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as cetuximab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Radiation therapy uses high-energy x-rays to kill tumor cells. Giving cisplatin, fluorouracil, and cetuximab together with radiation therapy may kill more tumor cells.

PURPOSE: This phase II trial is studying how well giving cisplatin, fluorouracil, and cetuximab together with radiation therapy works in treating patients with HIV and stage I, stage II, or stage III anal cancer.

Changes in viral load and CD4 counts during and for 1 year after completion of study treatment [ Time Frame: 1 year following treatment discontinuation ] [ Designated as safety issue: No ]

Incidence of opportunistic illnesses, including the development of AIDS during and for 1 year after completion of study treatment [ Time Frame: 1 year following treatment discontinuation ] [ Designated as safety issue: No ]

Cetuximab 400 mg/m2 IV Day -7 (1 week before the cycle 1, Day 1 cisplatin/5-FU and RT), then 250 mg/m2 IV Days 1, 8, 15, 22, 29, 36 and 43 (a minimum of 6 and a maximum of 8 doses of cetuximab will be administered, including the loading dose).

400 mg/m2 IV Day -7 (1 week before the cycle 1, Day 1 cisplatin/5-FU and RT), then 250 mg/m2 IV Days 1, 8, 15, 22, 29, 36 and 43 (a minimum of 6 and a maximum of 8 doses of cetuximab will be administered, including the loading dose)

Other Name: Erbitux

Drug: cisplatin

75 mg/m2 IV on Day 1 (cycle 1) and Day 29 (cycle 2)

Other Name: Platinol

Drug: fluorouracil

1000 mg/m2/day by continuous intravenous infusion on Days 1-4 (cycle 1) and Days 29-32 (cycle 2)

Other Names:

5-FU

Adrucil

Carac

Efudex

Fluoroplex

Radiation: radiation therapy

Irradiation to tumor site and inguinal nodes beginning on cycle 1, Day 1 cisplatin/5-FU (minimum 45.0 Gy [5 weeks if given on schedule and without interruption], maximum 54.0 Gy [6 weeks if given on schedule and without interruption). IMRT may be used at the discretion of the treating physician.

Characterize the effect of this regimen on the underlying HIV condition by describing changes in viral load, CD4 counts, and the incidence of opportunistic illnesses, including the development of AIDS during and in the first year after treatment.

Evaluate the effect of this regimen on anogenital human papilloma virus (HPV) infection and anal cytology.

OUTLINE: This is an open-label, multicenter study.

Patients receive cetuximab IV over 1-2 hours on days 1, 8, 15, 22, 29, and 35*, fluorouracil IV continuously on days 1-4 and 29-32, and cisplatin IV over 1 hour on days 1 and 29. Beginning on day 1, patients undergo concurrent radiotherapy to the primary tumor 5 days a week for 5-7 weeks. Treatment continues in the absence of disease progression or unacceptable toxicity.

NOTE: *Patients receiving 7 weeks of radiotherapy also receive cetuximab on days 42 and 49.

Quality of life is assessed at baseline, at the completion of study treatment, and then at months 3, 6, 12, 24, and 36.

After completion of study treatment, patients are followed periodically for 5 years.

PROJECTED ACCRUAL: A total of 47 patients will be accrued for this study.

Eligibility

Ages Eligible for Study:

18 Years and older

Genders Eligible for Study:

Both

Accepts Healthy Volunteers:

No

Criteria

DISEASE CHARACTERISTICS:

Histologically confirmed stage I-IIIB invasive anal canal or perianal (anal margin) squamous cell carcinoma, including tumors with any of the following nonkeratinizing histologies:

No other prior invasive malignancy diagnosed within the past 24 months, excluding in situ cervical cancer, anal dysplasia or carcinoma in situ, nonmelanoma skin carcinoma, or Kaposi's sarcoma that has not required systemic chemotherapy within the past 24 months

No peripheral neuropathy > grade 1

No severe or poorly controlled diarrhea

No medical or psychiatric illness that would preclude study requirements

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Please refer to this study by its ClinicalTrials.gov identifier: NCT00324415